Abstract: Objective To evaluate the correlation between the C1236T rs 1128503 polymorphism in the multidrug resistance 1 （MDR1） gene and primary liver cancer （PLC） in a Guangxi Zhuang population. Methods A case-control study of 109 PLC patients and 109 healthy controls was conducted in a Guangxi area with a high PLC incidence.Genotypes and alleles of MDR1 C1236T rs 1128503 were detected by matrix-assisted laser desorption ionization time-of-flight mass spectrometry（MALDI-TOF-MS）. Results The PLC and control group did not differ significantly in frequencies of MDR1 rs 1128503 CC，CT，or TT genotypes，or in frequencies of C and T alleles（P>0.05）.The frequencies of C and T alleles were 42.20% and 57.80%. Conclusions Risk of PLC is not increased in carriers of the MDR1 C1236T rs 1128503 CT or TT genotypes.MDR1 polymorphism may not be a genetic susceptibility factor for PLC.

Key words: Liver neoplasms, MDR1, C1236T, rs 1128503, Single nucleotide polymorphism